1. Field of the Invention
The invention relates to an intraocular lens for use as an artificial lens implant in the human eye.
2. Description of the Prior Art
The following U.S. patents disclose intraocular lens which employ different types of open loop or closed loop haptics or position fixation members: U.S. Pat. Nos. 4,010,496, 4,085,467, 4,159,546, 4,174,543, 4,242,760, 4,244,060, 4,251,887, 4,253,200, 4,280,232, 4,285,072, 4,298,994, 4,298,995, 4,304,012, 4,316,292, 4,328,595, 4,338,687, 4,340,979, 4,361,913, 4,370,760, 4,377,873, 4,418,431. The purpose of the haptics or position fixation members is to hold or support the optic or lens body in the eye in a stable position with respect to the pupil and visual axis. As pointed out in U.S. Pat. No. 4,418,431, a certain degree of flexibility of the haptics is desirable. In addition, a desirable feature of any intraocular lens is that it exhibits geometrically stable haptic flexion which consists of three basic properties: (1) no side to side movement of the haptic when it flexes; (2) no change in the location or amount of touch of the haptic with the tissue of the eye; (3) the haptic must be able to flex without movement of the optic forward, backward, or side ways when in the anterior or posterior chambers of the eye (uniplanar loop flexion). Very few of the known intraocular lenses have all of these properties. Previously, it had been thought that flexion of closed loop haptics owuld invariably result in anterior optic movement (movement of the optic forward) when placed in the anterior chamber of the eye. This is particularly true for lenses which are made in an angulated or vaulted design in order to support the lens away from the iris. Such anterior optic movement is undesirable since it may result in engagement of the optic with the cornea on its posterior surface which can result in damage to the cornea.